Recently, to realize high recording density, large capacity and miniaturization, magnetic disk devices have been adopted perpendicular magnetic recording methods. In a magnetic disk device adopting this method, a recording head conforming to perpendicular magnetic recording is opposed to a recording surface of a magnetic disk having a recording layer conforming to perpendicular magnetic recording, and data is recorded in a predetermined region of the magnetic disk by generating a perpendicular magnetic field corresponding to the recording data by the recording head.
Here, the recording head conforming to perpendicular magnetic recoding includes a main magnetic pole which has a narrowing portion formed of a soft magnetic material, a return magnetic pole which returns a magnetic flux from the main magnetic pole and forms a magnetic circuit in cooperation with the main magnetic pole, and a coil which excites a magnetic flux and generates a recording magnetic field in the magnetic circuit formed of the main magnetic pole and the return magnetic pole.
In the case of the recording head having the above-described structure, in a recording state, a projection is formed locally in a gap between the main magnetic pole and the return magnetic pole, and this projection may frequently contacts an abnormal projection of a recording medium. In particular, if a recording current has a high value, a diamond-like carbon (DCL) component tends to be worn or deposited on an air bearing surface (ABS) of the recording head, and the reliability has been suspected.
Embodiment aims to provide a magnetic disk device and a recording head control method which can prevent local projection formed in a gap between a main magnetic pole and a return magnetic pole during recording to the magnetic disk.